The long-term objectives of the project is to determine the abundance of airborne fungal spores within the atmosphere and gain an understanding of the mechanism by which spore development, spore survival and spore germination influence prevalence of clinically significant airborne fungal spores that are responsible human health problems such as allergic disorders, infections and mycotoxins. The specific objectives are (1) improve and expand the particle size analyzer-based rapid spore identification method, (2) increase the information bank about the atmospheric abundance of clinically and germination relevant to atmospheric occurrence. The Andersen atmospheric sampler will be used on a monthly schedule, to collect spores and subject them to a particle size analysis. To obtain a better understanding of the extent that spore development, spore survival and spore germination techniques of phase contrast, florescent scanning electron and transmission electron microscopies will be used to observe certain critical stages in wild type and mutant strain of the fungus, Coprinus cinereus. Because of its synchronous basidiospore development, ease of manipulation in the laboratory and production of both asexual and sexual spores, C. Cinereus will be used as a model for establishing "maker" events in development, survival and germination. Mutant strains will be used to highlight critical stages. Cladosporium, a frequently collected and abundant fungus, and Aspergillus a frequent but not abundant fungus will be studied along with C. Cinereus. These fungi will be exposed to simulated environmental stresses and analyzed perturbations at the cellular level. Knowing the extent to which environmental and intrinsic factors influence airborne fungal spore prevalence will provide the means for accurate estimates of fungal disease agents in the atmosphere.